The present disclosure relates to a semiconductor memory and a memory system, and more particularly to a semiconductor memory device including a ferroelectric random access memory (FeRAM).
Ferroelectric memory is a type of memory in which polarization inversion is used to retain information in a ferroelectric capacitor, and is a non-volatile memory in which the retained data is not lost even while power is not supplied thereto.
In a semiconductor memory device, in addition to a memory region, a peripheral circuit region is provided. Various circuits such as a logic circuit and a power supply circuit, and an A/D converter, each being made of a CMOS transistor, are provided in the peripheral circuit region. For example, smoothing capacitors are provided in the semiconductor memory device for the purpose of stabilizing power supply voltages to such circuits, etc. In a fabrication process for providing a memory in a semiconductor memory device, the smoothing capacitors are formed simultaneously with the formation of memory capacitors of memory cells, using the same material for both capacitors. For example, in Japanese Patent Publication No. 2008-10765 and Japanese Patent Publication No. 2003-332532, memory capacitors of dummy memory cells which do not function as memories are caused to be function as smoothing capacitors.